The violence, which began late Saturday and continued early Sunday, erupted after around 25,000 people marched from parliament to the prime minister's house, where some attempted to remove barricades around it with cranes, an AFP reporter at the scene said.

Police responded with tear gas and rubber bullets.

There were more than 39 policemen, 36 woman and five children among the injured," Khawaja said.

Islamabad police chief Khalid Khattak told AFP that police exercised restraint but the protesters were armed with axes, wire cutters and hammers.

"They had a crane and drove it until the entrance of the presidency. We are using only tear gas and firing rubber bullets where needed," Khattak said.

Railways minister Khawaja Saad Rafique said protesters tried to uproot the entry gate of the prime minister's house.

The protesters, led by cricketer-turned-politician Imran Khan and populist cleric Tahir-ul-Qadri, had been camped outside parliament house since August 15 demanding Prime Minister Nawaz Sharif quit amid allegations of vote rigging.

The crisis took on a new dimension earlier in the week after the government asked the powerful army to mediate, raising fears the military would use the situation to enact a "soft coup" and increase its dominance over civilian authorities.

Demonstrations have also erupted in the eastern city of Lahore and the port city of Karachi.

Protesters with batons have burned tyres and blocked roads in Lahore, an AFP reporter said. Police used batons and fired tear gas to disperse the demonstrators there.

NJF/NJF